Serena needed to showcase her legendary game to defeat Simona Halep

Serena knew she had to step it up in the third set (1:09)

Serena Williams talks about upping her game in the third set to defeat Simona Halep in the US Open quarterfinals. (1:09)

NEW YORK -- Top-ranked Serena Williams knew she hadn't dropped a set going into her quarterfinal showdown against Simona Halep. But that didn't stop Williams from channeling a little Goran Ivanisevic of old after her previous two US Open matches -- both romps. Williams wryly spoke about herself in the third person, claiming she was waiting for the "real" Serena to show up and how she dearly hoped it would be soon.

On Wednesday night, Williams finally got her wish in what might have been the most scintillating women's tennis match of the year.

After a torrid start in which it seemed she might run Halep right off the court, Williams needed every bit of her legendary game -- her service bombs, her defensive prowess and net play, the power ground strokes and delicate drop shots she parachuted down here and there -- to survive everything Halep started to throw at her during the 2 hours, 14 minutes they raged at each other on a muggy night at Arthur Ashe Stadium.

Until this match, no previous opponent had managed to keep Williams on-court more than 68 minutes. In the end, Williams knew she had only herself to blame for the length of this match. She went 0-for-12 on break points in the second set and double-faulted to hand Halep a decisive break of her own.

But it wasn't just that. The fifth-seeded Halep spectacularly took advantage of the openings Williams gave her. This was before Williams rose up just as spectacularly herself in the third set and eventually pulled away to a 6-2, 4-6, 6-3 win.

"I didn't play the same match in the second [set] that I did in the first," Williams said. "That's what makes me really calm. I feel like I can play so much better. I think everyone here knows I can play better.

"I was rather positive today -- and that's definitely not normal, but I'm just going to go with it," Williams joked with a comical roll of her eyes.

Though she wasn't asked about it once, the 34-year-old Williams is playing for a lot at this tournament. She has a chance to tie Chris Evert for the most US Open title wins ever, at seven. She has a chance to break a tie with Steffi Graf and get her 23rd career major win, a record for the Open era.

Williams already moved by Roger Federer a match ago for the most-ever Grand Slam tournament wins (she's now at 309 … and counting) but her hold on the No. 1 ranking for 186 consecutive weeks-- another record she shares with Graf -- is in jeopardy if she doesn't win this tournament and Angelique Kerber, whom she lost to at the Australian Open but beat in the Wimbledon final, does.

That's a lot of history in play. But it's almost peculiar how little such milestones are even talked about much anymore. Williams already owns so many, it's getting hard to keep track of them all. The bandwidth of her career has been so extraordinary for so long, it's starting to feel like one of those stories in which the script gets flipped.

The sum of all she has done is starting to feel greater than the parts.

Halep seemed to surrender to the same idea when asked to describe how this match got away from her.

"She is the best player," Halep said, as if the statement hardly needed any elaboration.

Halep is now 1-8 for her career against Williams but said she could at least walk away from this match knowing, "This was the best I ever had against her."

But Halep also knows her 105-mph serves pale next to the 120-plus bombs that Williams was smashing at her. And if she was ever going to win this match, it was going to have to happen the way it almost did: She'd have to be ready to chase down every ball Williams smashed back at her; she'd have to absorb the power Williams packs into her groundstrokes and snap off some winners herself; and she'd have to minimize her own mistakes and try to match Williams' will and hope Williams gave her a glimmer of daylight here and there.

And it nearly happened.

But in the end, another difference was Halep couldn't overcome failing to convert two service break points in the first game of the third set, but Williams finally broke her a few games after that.

Even an hour after the match, it was that missed opportunity that still stood out to the fifth-seeded Romanian. Said Halep: "If there I could take that game, I think the story of the match would've been different."

But she didn't. And it wasn't.

Williams will now move on to play 10-seed Karolina Plishkova, the WTA Tour leader in aces, Thursday night in a semifinal that is already being hyped as having the potential to deliver the most aces ever struck in a single women's match. It will be interesting to see how Williams' sore right shoulder, which has bothered her for weeks, will respond to back-to-back matches.

The second-seeded Kerber and resurgent Caroline Wozniacki meet in the night's other semifinal.

Williams was low-key Wednesday through much of her postmatch media conference -- even when reminded it was Plishkova who rallied to beat her sister Venus earlier in this tournament, depriving she and Serena of a chance to perhaps meet in a Slam semi for the first time in years. But Serena did seem a bit intrigued when a reporter went on to mention that Plishkova also has a sister who plays on tour -- but the Plishkovas are twins.

"Have you ever thought about another identical copy of you floating around, how tough that might be?" Serena was asked.

And the real Serena was indeed back.

"It would be a living hell," Williams cracked.